From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95586C11D0C for ; Thu, 20 Feb 2020 19:40:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BB87206F4 for ; Thu, 20 Feb 2020 19:40:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582227652; bh=ZF+yF3yQPqplRh3NGkt9AfosvVB37x7typbIEstBhrk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=AS0CpY1bYj8kCS0VKqvqjCRRQdRhUks9cQkHJulRNJeiKjLyawwmZ85a6epAztmCP TtqcEHZH4V4wvqGx5UYKsYQP3km3JN2NDiU6ho+ZPQfYaFI1Z8YEwBa6M5utxN3r91 KBIFxRvF4f6T/ElZbVL/0pvAQGsSr0m+cj3dlLQg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728695AbgBTTkv (ORCPT ); Thu, 20 Feb 2020 14:40:51 -0500 Received: from foss.arm.com ([217.140.110.172]:50256 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728248AbgBTTkv (ORCPT ); Thu, 20 Feb 2020 14:40:51 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4C38530E; Thu, 20 Feb 2020 11:40:50 -0800 (PST) Received: from localhost (unknown [10.37.6.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B5DB73F6CF; Thu, 20 Feb 2020 11:40:49 -0800 (PST) Date: Thu, 20 Feb 2020 19:40:48 +0000 From: Mark Brown To: Dan Murphy Cc: lgirdwood@gmail.com, perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ASoC: tas2562: Add support for digital volume control Message-ID: <20200220194048.GI3926@sirena.org.uk> References: <20200220172721.10547-1-dmurphy@ti.com> <20200220184507.GF3926@sirena.org.uk> <20200220191803.GH3926@sirena.org.uk> <6f3ff810-5e75-cb33-10d6-198a7c5cd202@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Op27XXJsWz80g3oF" Content-Disposition: inline In-Reply-To: <6f3ff810-5e75-cb33-10d6-198a7c5cd202@ti.com> X-Cookie: You are number 6! Who is number one? User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Op27XXJsWz80g3oF Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Feb 20, 2020 at 01:22:34PM -0600, Dan Murphy wrote: > On 2/20/20 1:18 PM, Mark Brown wrote: > > decisions causing changes in the driver. The system may have an > > external amplifier they prefer to use for hardware volume control, may > > prefer to do entirely soft volume control in their sound server or > > something like that. > But this is an amplifier.=A0 Not sure why the system designer would design > cascading amplifiers. > And if that was the case wouldn't you want the output to be low so you do= n't > overdrive the ext amplifier front end? The point is that we don't know what people are doing and should try to keep the kernel out of policy decisions unless there's something that's clearly just unconditionaly right for all systems. It's a lot easier to just have a clear rule that we defer to the wisdom of the silicon vendor than try to get into defaults, and it's a lot easier to just do this as consistently as we can rather than debating individual configuration changes. > I was considering safety in that the device is on at full blast (not sure > why the HW is defaulted that way but it is). I bet there's been issues with people turning things on and not realising they need register writes to hear anything, and the volume control here is a bit complex as well. > But if volume is adjusted prior to playback then this is not an issue.=A0= But > if volume is not adjusted then it plays full blast. Wouldn't be the first time. See all the dual purpose headphone/line outputs that people build, sensible defaults for headphones and line outputs are rather different. --Op27XXJsWz80g3oF Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl5O4L8ACgkQJNaLcl1U h9A7ywf/a70pEqcaoFyz44HUYWAA/C7/HptVOyj9BF7YOHzPCROQheZtAOnK/irB NQ/wVoUly0UK4lakCGKSiAOvpqJIQ0XTEWP8KYt/SnA8jTsehWTlJaOlDuotsnOw e3hQkhBz03kXfyuNO0VdGEbmIivWqb5rgzVykCYo0wS1qSYKFITdIKyK6uvLfDnX g0l/AQmep2hERqDbM0g+zi8vOtgabdblq2/q93zTwEJidA2C7dpJBs/BpelKxzT1 I3sDvPo3XXCCKdLjiMi6Bp6e9tlZ4qcly412+bMUfCJjCKOYOgH3jsGdG4M87UR+ wvOv3ovPVjWTsSaVrlzJjFPabYYauQ== =NqJ2 -----END PGP SIGNATURE----- --Op27XXJsWz80g3oF--